I've been using the Intermatic DT620 for nearly two years now and have seen the timers lose an average of 10-15 minutes per year. Other than that, they have worked flawlessly for my clients. Overall, I'm quite happy with them.

Ok. Good. Then I'm not crazy. You're experiencing the same problem. That's good confirmation. Thank you.

Bill, I'm curious. Do you ever use the outdoor unit? The one I just posted below? As near as I can tell it's essentially the same timer. Same programming and everything. Just a different shell. I wonder if these have the same issue being 10-15 minutes off.

Jim,
I haven't used the outdoor version as of yet. I recently upgraded a halogen lighting system to LED and the customer has an outdoor version mounted in his garage controlling the transformer. I'll ask him if he has noticed any loss of time, but I doubt he pays much attention to it. He doesn't live there full time.

I've used that model that I posted above about 10 times over the last few years. Seems to be pretty good. I have 3 of them installed at my house. Two on lighting transformers and 1 on my water feature.

I never really thought about the two outlets on the bottom much. Are those controlled by the astrological timer as well? So the Christmas lights would come on and off at the same time as the outdoor lighting system? That's kinda cool. (Although we don't install Christmas lights).

OK Jim, so how is that you used the "outdoor" one sometimes and the DT-620 other times? It has been my understanding that the batteries in the "outdoor" one could not take freezing temperatures but that the DT-620 does not have that problem because of being in the transformer case where it is enough warmer.

OK Jim, so how is that you used the "outdoor" one sometimes and the DT-620 other times? It has been my understanding that the batteries in the "outdoor" one could not take freezing temperatures but that the DT-620 does not have that problem because of being in the transformer case where it is enough warmer.